Application of 3D-FDTD to the analysis of microstrip circuits including active nonlinear devices

In this paper, a 3D-FDTD method for the analysis of microwave circuits including active nonlinear devices is proposed. The relationship between electromagnetic fields and voltage sources is described according to Faraday's law, and then ports of microstrips are modeled by equivalent voltage sources. In order to connect active nonlinear devices to the voltage sources, equivalent circuits of the devices are employed. An example with a diode was analyzed and some reasonable time-domain results are obtained. The experimental studies are on going.